Sectional concrete forms



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United States Patent SECTIONAL CONCRETE FORMS Arthur C. Avril, Wyoming,Ohio, assignor to A and T Development Corporation, St. Bernard, Ohio, acorporation of Ohio Application March 21, 1952, Serial No. 277,830

Claims. (Cl. 25131) This invention relates to the art of erecting pouredconcrete structures and buildings and is directed particularly to animproved metallic form of sectional construction for molding the wallsof the building. The same metallic forms are utilized without change inmolding a concrete roof slab upon the building; thus, the number of formunits per building and the attendant expense is substantially less thanin conventional practice.

The method aspects of erection are disclosed and claimed in thecopending application of Arthur C. Avril, Serial No. 85,748, filed April6, 1949, now abandoned. The present application is directed to the novelfeatures of the form and is a division of the copending application.

The principal object of the invention has been to provide improvedsectional forms or molds for utilization in practicing the method, theforms being sectional in the sense that they are adapted to be installedin horizontal courses one upon another, whereby the concrete may bepoured into them and tamped in individual courses of controlled depth toprovide maximum density, strength and smoothness of finish. Essentially,each sectional form comprises an outside and inside section, thesections being installed in spaced relationship to delineate the wallthickness and configuration.

Another object has been to provide a form structure capable oftelescopic length adjustment so that the forms accommodate themselves tovariations in the spacing of preset columns which, in practicing themethod, constitute the skeleton of the Wall. This feature also adaptsthe forms, without refabrication or structural change, to variations inthe length of the building so that the forms are applicable topractically any concrete wall construction regardless of size.

A further object has been to provide a combined form tie and spacer ofsimple construction, adapted to clamp the forms against the precastcolumns on opposite sides whereby the form ties maintain accurately thespacing of the forms and thereby control the wall thickness. In theirutility as tie bars, they have the additional function of fastening thehorizontal courses of forms securely to one another and therebyfacilitate the installation of the forms in a single operation.

Still another object has been to provide a configuration around themarginal edges of the forms which impresses into the wall surface ageometric design which serves to conceal any slight irregularity whichotherwise might be apparent along the parting lines of the forms.

The marginal configuration has the added utility of imparting strengthand rigidity to the forms without materially increasing their weight orcost.

Described briefly, the erection method in which the forms are used,consists of first installing a foundation or footing and then erectingupon the footing, a series of precast concrete columns spaced from oneanother to delineate the skeleton of the wall. After the columns areplumbed and braced, with their lower ends grouted in sockets previouslyformed in the footing, the inner and outer wall forms are installed uponthe opposite sides of the columns with the first course of forms restingdirectly upon the footing. The forms so installed provide a shallowtrough into which the wet concrete is poured and tamped, thus bondingthe first course to the footing. This procedure is repeated byinstalling successive courses of forms upon the first course and pouringand tamping each added course before the next is erected.

By this method, the precast columns provide guides which, in conjunctionwith the forms, delineate the contour and thickness of the walls. Thecolumns become embedded as an integral part of the walls after they arepoured. In practicing the method, it is usual to erect a Wall sectionconcurrently in adjacent bays (delineated by the precast columns) bypouring concrete in the forms of one bay while a course of forms isbeing erected in the adjacent bay. This alternate pouring and formerecting procedure may be followed in one or several parts of thebuilding depending upon its size and the number of men employed on thejob so that the building is erected quickly with a minimum waste ofmanpower.

This method, which is made possible by the present forms, has severaladvantages over the conventional practice of erecting wooden forms ofwhich the following are considered the most pertinent:

First, by erecting the precast columns and using them as guides for theforms, the time and expense of having skilled craftsmen set Wooden formsis entirely eliminated, making it possible to execute the major portionof the construction work rapidly and accurately with unskilled labor.

Secondly, the procedure of pouringand tamping each courseindividuallyproduces a more uniform mixture of concrete throughout the wall andconsequently creates a stronger wall using a given amount of concrete.

Thirdly, individual course pouring and tamping produces-localizedagitation and increased pressure in each individual form course. Thiscauses the finer concrete particles to ;be brought intointimate contactwith the surface of the forms to provide a smooth architectural finishinstead of the naked appearance associated with the usual pouredconcrete wall.

In general, the present form structure consists of sheet metal panelsformed in sections telescopically interfitted to provide thelongitudinal adjustment; thus, the forms may be adjusted longitudinallyinto the spaces intervening between the precast columns to bring theends of the forms into abutment with the columns accurately and in asimple convenient manner. The spacer or tie bars draw and clamp theinner and outer forms firmly toward each other with their ends engagedagainst the inner and outer surfaces of adjacent columns.

The spacer bars, which are formed from sheet metal, are arranged tospace and align the successive courses of forms accurately in verticalplane with respect to one another. To fasten the spaced forms together,the spacer bars have outer end extensions which are adapted to beclinched over upon marginal flanges formed along the horizontal edges ofthe forms.

After the concrete has set, the clinched ends are released from theedges of the forms so that the forms can be removed; however, the spacerbars proper remain embedded in the concrete wall. When the forms areremoved, the extended ends of the spacer bars may be either broken offflush with the surface of the wall or they may be used to mount metalplaster lath by clinching over the end extensions upon the lath.

The geometric pattern which is impressed in the external wall surfaceconsists of related vertical and horizontal grooves, generally V-shapedin cross section. The horizontal grooves correspond to the horizontalparting lines and the vertical grooves correspond to the vertical endsof the forms which abut the precast columns. Thus, the

vertical grooves are formed along the side edges of the precast columnsto conceal any irregularity which may exist between the plane of theform and the outer surface of the column. The configuration of both theexterior and internal wall surfaces presents a smooth texturedarchitectural finish having a pleasing pattern without requiring theadditional surface coating customarily applied to poured concretestructures.

As disclosed in the mpending application, the lower courses of forms,after the concrete in them has set permanently, are removed and iinstalled in leapfrog fashion from the lower upon the upper portions ofthe wall. In this manner the quantity of forms for a given size buildingand the attendant expense is reduced to a fraction of the cost offormsfor the'full height of the building.

The costof forms is further reduced by reusing them in pouring theconcrete roof slab. When the walls are completely erected, roof beams,similar to the precast columns,

are installed across the walls in position to support the opposite endsof the forms. The wall forms provide a depressed panel in the ceilingwhich matches the configuration of the inside wall surfaces to providean attractive appearance.

Further advantages and features of the invention are disclosed in thespecification with reference to the drawings in which: 7

Figure 1 is a side elevation of one of the extensible end panels of theinterior form assemblies.

Figure 2 is a side elevation similar to Figure 1 of an intermediate formpanel adapted to nest with a pair of.

the end panels of Figure 1 to provide an extensible form assembly.

Figure 3 is a side elevation of one of the extensible end panels of theexterior form assembly.

Figure 4 is a side elevation of'an intermediate panel adapted to nestwith a pair of the end panels of Figure 3 to form an extensible outsideform assembly.

Figure 5 is an end View of the panel illustrated in Figure 1.,

Figure. 6 is an end view of the intermediate panel illustrated in Figure2. V

Figure 7 is an end view of the fpanel'illustfated' in Figure 3.

Figure 8 is an end view of the panel illustrated in Figure 4.

Figure 9 is an enlarged fragmentary view of a portion of a concretebuilding wall as viewed from the'gexterior,

' showing the precast columns with several courses of forms installedand showing a portion of the finished exterior wall with the formsremoved.

Figure'lO is a view similar to Figure 9 showing the interior forms and aportion of the finished wall pattern. 7

Figure 11 is a longitudinal section view taken along line 1111, Figure10, illustrating'in greater detail the relationship of the assembledinterior and exterior form assemblies.

Figure 12 is an enlarged fragmentary section view taken along line12-12, Figure 10, showing two courses of forms erected and poured withthe third course installed and ready for pouring. V

Figure 13 is a sectional view similar to Figure 12 showing the third'form poured and showing a vertical reinforcing rod'in place in thewall.

Figure 14 is a view similar to Figure 12 showing the fourth course offorms installedrand ready for pouring.

Figure. 15 is a fragmentary sectional view illustrating a portion of theroof slab, and showing the mode of utilizing the interior wall forms formolding the slab.

Figure 16 is a top plan .view of the building showing the formsinstalled and thereof slab partially poured as indicated in Figure 15.

Figure 17 is a perspective View showing one of the form ties used in thefirst course of forms, the he being placed directly upon the footingwith its ends clinched over horizontal grooves 24a in the wall surface.

form unit comprises. an exterior assembly indicated gen-.

crally at 16 and-an interior assembly 11. The exterior assembly 10consists of two end panels 12-12 (Figure 3) and an intermediate panel 13(Figure 4) which overlies the adjacent inner portions of the end panelsto provide the length adjustment. The interior assembly similarlyconsists of two end panels 14-14- (Figure 1) and an overlyingintermediate panel 15 (Figure 2).

The three panels of each form assembly are preferably .forms of sheetsteel and upon installation, cooperate with one another to moldtheexterior and interior wall surfaces. In order to provide individualform installation and controlled pouring depth, the forms in assemblyprovide troughs which in the present embodiment are twelve inches deepand sutficiently long to fit between adjacent precast columns. I

As best shown in Figure 11, the interior and exterior form assembliesare installed at opposite sides of the precast columns 16 which areinstalled in the footing 17 to provide guides for the forms duringerection of the wall. By reason of their length adjustment, the oppositeends of the forms assemblies are partially overlapped on opposite sidesof the columns in the plane of the wall. Internal 1 stops are formed onthe internal surface of the forms successive courses of forms duringerection as shown in Figures 12 to 14 and remain embedded in the wallafter the forms are'removed. .The forms are shaped to impress inassembly the grooved surface pattern in the exterior wall surface asdisclosed. in Figure 9 and the panelled pattern in the interior wallsurface as disclosed in Figure 10. V

Each end panel 12 and 14' of'the form assemblies includes right angularflanges 2121 extending outwardly along its. opposite horizontal edgesand a similar flange 22 extending vertically along its outer end.This'leaves the end 23 open so that the intermediate panels 13 and 15(Figure 11) may be fitted telescopically between the horizontal.marginal flanges 21'21. The horizontal flanges 21-21 also provide seatsto sustain the courses of forms one uponanother and provide the meansengaged by the form ties to secure the courses together. 7

The panels 12 further include horizontal corrugations 24, generallyV-shaped in cross section, extending inwardly from the face of the panelin' a direction opposite to the. flanges .21. At the right end of thispanel, as

'jacent side of the column.

As shown in Figure 3, the vertical corrugation 25' at the right end ofthe panel, impresses a vertical V-shaped groove 26a (Figure 9) in thewall surface outlining the columns 16. The horizontal corrugations Z4impress the As best shown in Figure 7, the'horizontal corrugations24'form a part of the flanges 21 so that when placed in superposedcourses, the channels at the meeting flanges complement of the oneanother to form the V-shaped grooves in the wall. Thus, the joints atthe meeting lines of the forms, which otherwise would form lines in thewall, are concealed by the depressed V-shaped grooves, and slightvariations in the plane of the wall which are inconsequential but marthe appearance of it, are not evident. The left end of panel 12, asviewed in Figure 3, also is provided with a corrugation 27 so as toimpress in the wall surface a vertical groove delineating the areamolded by the intermediate panel 13. i

As shown in Figure 4, intermediate panel 13 is provided with marginalflanges 2828 extending from its outside surface, and includes V-shapedhorizontal corrugations 30-30 extending from its inside surface. Thehorizontal corrugations 30 are adapted to nest in the horizontalcorrugations 24 of the end panels 12 so as to form continuous groovesacross the wall surface which is molded by the end and intermediatepanels in assembly.

The interior form asemblies are substantially the same as the exteriorones except that there is provided a depression to impress in the wallsurface a panelled configuration. Each interior assembly consists of apair of the extensible end panels 1414 and an intermediate panel 15,generally similar to the exterior assemblies as above noted. Referringto Figures 1 and 5, the end panels 14 each include a central depressedportion 31 to stiffen the form and delineate the depressed panel 31a(Figure in the interior wall surface. The horizontal marginal offsetportions 32-32 adjoining the flanges 21 from the horizontal ribs 320 inthe wall surface between :panels. This construction provides maximumstrength,

reduces the volume of concrete used in the construction of the buildingand provides. an attractive interior surface pattern. As shown in Figure1, the flange 21 is omitted at the left end of panel 14 so as to permitthe intermediate panel to be telescopically interfltted between thehorizontal flanges 21-21 with its ends overlying the exterior surface ofpanel 14, as shown in Figure 11, to permit longitudinal adjustment.

As shown in Figure 11, the space 33 intervening between the ends oftheinterior panels 1414, which is covered by the intermediate panel 15,produces a vertical column of concrete between the panels. A similarconcrete column is produced in the exterior wall surface at the space 34intervening between the exterior panels.

'It will be observed that the telescopic relationship of the panelspermits the wall sections between the columns to vary in length, thisvariation being conveniently accommodated by extending or retracting theend panels relative to the intermediate panel.

The forms are clamped in spaced relationship by means of the form tiesdetailed in Figures 17 to 19. These are placed along the adjoininghorizontal flanges with their ends crimped over upon the flanges ashereinafter described.

The spacer or form tie 18 for the bottom course is in the form of asheet metal angle bar having a vertical flange 35 and a pair of flatextensions 36-36 at opposite ends. These spacers are placed between thefooting 17 and first course of forms (Figure 12) with the flange 35extending upwardly and spanning the inner and outer form assemblies tospace them. The spacers are applied in the central portion of the formsas viewed in Figures 9, 10 and 12 so that the end extensions may beclinched over upon the meeting flanges of the end panels andintermediate panels as indicated at 37 (Figure 12) to secure the formpanels firmly together and hold them in spaced relationship. Spacers 19are then placed upon the upper flanges of the asesmblies to secure themtogether as detailed later.

The spacers or form ties 19 for theupper courses of forms are made fromsheet metal stampings providing an upwardly extending spacer flange 38along one edge and a downwardly extending flange 40 along the oppositeedge. 'When placed upon the top of the first course (Figure 12), theupward flange 33 forms a spacer for the next course of forms, and thelower flange 40 extends downwardly to space the upper edge of the bottomcourse. Spacers 19 are used for all the forms above the bottom course asshown in Figures 12 to 14. It will be noted that spacer 19 is providedwith end extensions 4141, each split longitudinally along the line 42 tothe aperture 43. This provides a pair of ductile limbs 44-44, one ofwhich is adapted to be bent downwardly and doubled around the flanges ofthe forms upon which the spacer is placed. The other limb subsequentlyis bent upwardly and doubled around the flanges of the succeeding set offorms when they are installed. These clinched extensions are indicatedat 41a in the drawings.

The tie bars 20, detailed in Figure 19, are in the form of flat sheetmetal strips. They are used to tie the end panels of the form assembliestogether as shown in Figure 11. These strips are placed between themeeting flanges of the forms and their opposite ends are doubled overupon the flanges to draw the forms toward each other into engagementagainst the opposite sides of the columns 16. In other words, the tiebars pull the forms together and the spacing is maintained by the columnon one end and by the intermediate spacers 18 or 19 on the other end.

During the erection and pouring of the concrete courses, horizontalsteel reinforcement rods 45 may be installed along the wall so as to bepositioned approximately in a central plane between the forms (Figures12 to 14). These rods extend through apertures 46 formed in the columns16. In practice, the rods are made somewhat longer than the spaceintervening between the columns so that the rods pass through theaperture and overlap each other between the columns, with the overlappedends wired together if desired.

After several courses of concrete have been poured, vertical steelreinforcement rods 47 are. installed by thrusting them through the softconcrete as shown in Figures 13 and 14. The vertical rods are somewhatlonger than the height of the walls so that their upper ends Will extendabove the top to be interconnected with the roof slab.

Door and window openings are formed in the wall by installing breachforms at selected points between the spaced Wall forms to mold thenecessary openings. A structure for this purpose is disclosed in thecopending application of Arthur C. Avril, Serial No. 170,760, entitledForms for Molding Openings in Concrete Structures, filed on June 28,1950, to which attention is invited. The breach forms were developed foruse with the present wall forms and are sectional in the same manner sothat they can be installed piecemeal in successive courses of wallforms. The breach forms are approximately the same width as the spacingbetween the installed wall forms and their opposite side edges areshaped to fit the internal contour of the forms to prevent leakage ofconcrete. The breach forms are inserted between the wall forms todelineate the height and width of the required opening and are laterremoved with the wall forms.

When the wall forms are to be removed, the end extensions of the spacersand tie bars are straightened out so as to disengage the flanges of theforms. It will be observed that the spacers are left embedded in thewall permanently and after removing the forms, these extensions may bebroken ofi flush with the wall either with a cutting tool or by bendingthem back and forth t cause crystallization and breakage.

After the walls are erected, a concrete slab roof may be poured, usingthe inside form panels 14 as'roof slab forms. If the building is to bemore than a single storied structure, a concrete floor, formed in thesame manner as the roof, is poured, and the walls of the second storybeams or purlins 48 which are somewhat thicker than the'vertical columns16. These purlins are placed in slots formed in the upper edge of thewall so that the upper surface of the purlins is substantially flushwith the top of the wall. After these members are installed, the formpanels 14 are mounted between them to support the roof slab, which ispoured directly into the forms.

As shown, the forms 14 extend from the inside surface of the walls, withone end supported by vertically ad justable columns or shoring members50 having stringers 51 to support the forms. The oppositeends of theforms are supported by rails such as wood two by fours 52,

clamped upon opposite sides of the purlins by C-clamps 53. The purlins48 are spaced apart to receive the forms lengthwise between them andthere are provided as many purlins as the dimension of the buildingrequires. The intermediate'rows of forms have both ends supported by thepurlins, each purlin being provided with rails 52 for supportingopposite ends of the forms.

To prevent sagging under the weight load of the concrete, the forms aresupported intermediately by means of scafloldin'g, generally indicatedat 54 and beams 54a. After the scaifold is installed, a rail 55 isinstalled upon the top of the wall to form a curbing or closure toretain the concrete, which is flowable when poured. The roof slab isreinforced by longitudinal and transverse reinforcement rods and 57placed upon the forms as shown in Figure 16. After the roof slabhas setthoroughly, the scafiold 54 and shoring members 50 are removed so thatthe forms may be dropped downwardly and removed. The form contourprovides a panelled ceiling which provides maximum strength for thevolume of concrete employed and presents an attractive pattern 7matching the interior walls.

The telescopic forms are constructed to conform to the present daymodular construction system, the forms having a minimum length of eightfeet according to the prevailing unit of measurement or multiple used inlocating I-beams and columns from center to center. Following the systemtherefore, the precast roof rafters are placed at eight feet centersconforming to the length of the form sections.

In wall construction, the number of form ties is determined by theparticular requirements of the job; thus, the spacers may be placed atany desired point along the forms as needed. In the interest of economy,the form ties are formed from light gauge metal, for example, number 16gauge, thus reducing the crevice between forms *to a minimum to preventleakage of concrete.

. Maximum lightness of spacers is possible because the pressure islocalized in each course of forms and after two or three courses havebeen poured, .the lower courses have set sufficiently to sustain thecourses above without transmitting a cumulative load to the lower ones.

It will be understood that the telescopic relationship of the formpanels permits the form assemblies to be adjusted and installed in asimple manner even though the spacing of the columns may be irregulardue to the design of the building. This of course lends flexibility andmakes it possible to use the standard form units for practically anytype of wall construction regardless of length, elevation or thickness.The adaptability of the forms to meet these variable factors naturallyeffects a saving in costs since the basic form assembly is astandardized production item of low cost construction.

The adaptabilityof the forms is further enhanced by the simplicity ofthe form ties and convenient random installation. As the successive formassembliesare in- 8 stalled, the form ties, which areconcurrentlyinstalled, maintain the intermediate portions of the formsprecisely in the same spaced relationship as the end portions whichembrace the opposite sides of the precast columns;

As indicated in Figure 12, the intermediate ties are simply placed uponthe upper edge of the overlapped panels, then one of the split endextensions is clinched downwardly over the meeting flanges of theintermediate and end panels. Thus, the form ties hold the panels inassembly and also space them accurately 'at opposite sides in a singleclinching operation.

After the form is poured and tamped, the next course of forms isinstalled, then thesecond of the end extensions is clinched over uponthe lower flanges of the new course so that the panels of the new courseare fastened securely in assembly and in plane with the lower course.This procedure is repeated with the installation of each course andthereby accurately spaces and aligns the form' assemblies with oneanother by a simple clinching operation which is executed by a pliers orsimilar hand tool. The ties are left embedded in the finished wall afterthe concrete sets and if the interior'wall surface is to be plastered,metal plaster lath may be slipped over upon the extended ends of theties and secured in place by clinching the ends over upon the lath. Theends of the ties project from the exterior wall surface from the apex ofthe horizontal V-shaped groove and are easily broken off by bending themseveral times to crystallize the metal.

By virtue of the localized tamping of the individual form coursa madepossible by the present invention, the

finer particles of the concrete mix are worked outwardly into intimatecontact with the smooth metal surfaces of the forms to produce a finesurface finish which is equivalent or superior to the usualarchitecturalfinish applied by hand to ordinary poured concrete walls. The finefinish combined with the geometric surface pattern of lines and panelsproduces a highly attractive architec tural effect comparable only tosurfaces which are finished by skilled craftsmen. 7

Having described my invention, I claim:

1. A sectional form structure adapted to extend between adjacentvertical columns in clamping engagement against the opposite sidesthereof for molding successive horizontal courses of concrete one uponanother to form a wall between adjacent vertical columns, said formstructure comprising, respective inner and outer form assemblies eachform assembly constituting an elongated to stiffen the same, saidflanges providing a seat adapting I said form assemblies to be placedone upon the other in courses, and a series of spacers adapted to beplaced transversely across the inner and outer form assemblies, each ofsaid spacers including a pair of flanges extending upwardly anddownwardly adapted to extend in endwise abutment against the formassemblies to engage the internal upper and lower edge portions ofadjacent courses, said spacers including flat sheet metal extensionstrips at opposite ends adapted to be interposed between the meetingflanges of the superposed form assemblies and to extend beyond saidflanges, said extensions being split longitudinally to form a pairof'limbs,said limbs being doubled over in opposite directions around theflanges to secure the superposed assemblies together in the verticalplane and clamping the flanges of the intermediate and end panels inassembly and in longitudinal adjustment.

2. A spacer for securing together spaced inner and outer concrete forms,said forms having longitudinal flanges extending outwardly along theiropposite longi-' tudinal edges and adapted to be placed in successivehorizontal courses one upon another with said flanges superposed, saidspacer comprising, a flat sheet metal strip having an upwardly extendingspacer flange formed along one longitudinal edge and a downwardlyextending spacer flange along the opposite longitudinal edge, a fiatextension strip extending outwardly from opposite ends of the stripbeyond said flanges and adapted to be placed upon the longitudinalflanges of the forms with the downwardly extending spacer flangedisposed transversely across the upper edges of the inner and outerforms, the opposite ends of the spacer flange being in abutment with theinternal surface of the inner and outer forms and adapted to hold thesame in spaced relationship, the upwardly extending spacer flange beingadapted to extend across the lower edges of the next succeeding courseof forms, the opposite ends of the spacer flange being in abuunent withthe internal surface of the forms to hold the same in spacedrelationship, said flat extension strip being split longitudinally toform a pair of ductile limbs at opposite ends of the spacer arranged tobe clinched respectively downwardly and upwardly over upon thesuperposed flanges of the courses of forms to clamp the same in spacedrelationship and to secure the superposed courses together.

3. A form structure for erecting a wall by molding horizontal courses ofconcrete successively upon a footing and upon one another, said formstructure comprising, a series of columns rising vertically from thefooting and spaced apart from one another, said columns having athickness equal to the wall thickness and delineating the same, aplurality of courses of inner and outer forms mounted one above theother in vertical planes on opposite sides of adjacent columns andoverlapping the columns, the forms having a width less than twice thethickness of the columns, the forms spanning the columns horizontallyand providing a mold chamber between the columns with the columnsproviding end closures of the chamber, each inner and outer form havinga horizontal flange along opposite longitudinal edges projectingexternally from the mold chamber, the flanges providing seats supportingsuccessive horizontal courses of inner and outer forms one upon another,a series of form ties extending transversely across the inner and outerforms, each form tie having flat sheet metal extension strips atopposite ends interposed between the flanges of the successive coursesof forms in the plane thereof and projecting outwardly from said flangeson opposite sides, the sheet metal extension strips providing aninterface between the flanges which is sufliciently narrow to preventthe escape of wet concrete from between the forms, the form ties havingspaced abutments at opposite ends projecting upwardly and downwardlyrelative to said flanges and engaging the internal surface of the formsalong the interfaces thereof, the spacing of said abutments related tothe thickness of the columns and cooperating with the columns todelineate the thickness of the wall, the said sheet metal extensionstrips of the form ties each comprising a pair of limbs which aredoubled over in opposite directions and clinched upon the seated flangesof successive courses of forms, thereby securing the seated flanges toone another and clamping the forms against the said spaced abutments.

4. A form structure for erecting a wall for molding horizontal coursesof concrete successively upon a footing and upon one another, said formstructure comprising, a series of columns rising vertically from thefooting and spaced apart from one another, said columns having athickness equal to the wall thickness and delineating the same, aplurality of courses of inner and outer forms mounted one above theother in vertical planes on opposite sides of adjacent columns andoverlapping the columns, the forms having a width less than twice thethickness of the columns, the forms spanning the columns horizontallyand providing a mold chamber between the columns with the columnsproviding end closures of the chamber, each inner and outer form havinga horizon tal flange along opposite longitudinal edges projectingexternally from the mold chamber, the flanges providing seats supportingsuccessive horizontal courses of inner and outer forms one upon another,a series of form ties extending transversely across the inner and outerforms, each form tie including flat sheet metal extrusion strips atopposite ends interposed between the seated flanges of the courses offorms, said extensions split longitudinally to form a pair of limbs,said limbs doubled over in opposite directions around the seated flangesand clinched thereon to secure the forms together, the form ties havingspaced abutments at opposite ends projecting upwardly and downwardlyrelative to said flanges and engaging the internal surface of thecourses of forms, the spacing of the abutments related to the thicknessof the columns and cooperating with the columns to delineate thethickness of the wall.

5. A form structure for erecting a wall by molding horizontal courses ofconcrete successively upon a footing and upon one another, said formstructure comprising, a series of columns rising vertically from thefooting and spaced apart from one another, the columns having athickness equal to the wall thickness and delineating the same,respective horizontal courses of inner and outer forms mounted one abovethe other in vertical planes on opposite sides of adjacent columns andoverlapping the columns, the forms spanning the columns horizontally andproviding a mold chamber between the columns with the columns providingthe end closures of the chamber, each form having a horizontal flangealong opposite longitudinal edges projecting externally from the moldchamber upon opposite sides thereof, the flanges providing seatssupporting successive horizontal courses of forms one upon another theforms along one side of the wall having, respective corrugations formedin the opposite longitudinal edges thereof, said corrugations adjoiningsaid flanges, each of said corrugations rising at an angle inwardly fromthe internal plane of the form adjacent the flange and joining the inneredge of the flange, each corrugation being complementary to thecorrugation of the adjoining course of forms, said complementarycorrugations in assembly forming a generally V-shaped corrugation havingan apex projecting inwardly along said seated flanges, said corrugationimpressing a V-shaped groove in the wall along said flanges, and aseries of form ties extending transversely across the inner and outerforms, each form tie having flat metal extension strips at opposite endsinterposed between the flanges of the successive courses of forms, eachform tie having spaced abutments at opposite ends engaging the internalsurface of the successive courses of forms along one side of the walland the apex of said corrugations, along the opposite side, the spacingof the abutments related to the thickness of the columns and cooperatingwith the columns to delineate the thickness of the wall, the flat metalextension strips of the form ties each comprising a pair of limbsdoubled over in opposite directions and clinched upon the seated flangesof the successive courses of forms, securing the flanges together andclamping the inner and outer forms against said abutments.

References Cited in the file of this patent UNITED STATES PATENTS Re.17,733 Nelson July 15, 1930 645,325 McNamee Mar. 13, 1900 828,031 KemperAug. 7, 1906 830,747 Staufer Sept. 11, 1906 1,013,632 Whitthoefft Jan.2, 1912 1,126,190 Fuehrer Jan. 26, 1915 1,190,977 Bartow July 11, 1916(Other references on following page) 11 UNITED STATES PATENTS Colt Feb.27,1917 weiderhold Apr. 2, 1918 Fluor Feb. 8, 1921 Cummings Aug. 25,1925 Bauschard Nov. 29, 1927 Bierhaalder Dec. 9, 1930 Berton -1- Nov.

12 V Penote July 14, 1931 Heller Mar. 15, 1932 Troiel Oct. 15, 1935Thorn Nov. 19, 1935 Oldreive ;Ap1'. 24, 1945 14, 1950

